Difference between bpy.data.objects['Armature'] and bpy.data.armatures['Armature']
Document here
bpy_types.Object is a container wrapper for inner data to communicate with Blender Scene and other stuff.
You can rename your bone and armature:

&gt;&gt;&gt; C.object
bpy.data.objects['Obj Armature']

&gt;&gt;&gt; C.object.data
bpy.data.armatures['Real Armature']

And with the tree display in outliner, that should be clear that Object has Pose properties and the armature itself doesn't.